Aluminum alloy



Patented Mar. 18, 1930 1515M UNITED STATES PATENT ure er;

ANDRE GEYER, F PARIS, FRANCE ALUMINUM ALLOY No Drawing. Applicationfiled June 25, 1927, Serial No. 201,564, and in France February t, 1192?It is well known that in order to obtain There may be added to the bathpowdered unusually light aluminum alloys having recharcoal moistenedwith water, the hydromarkable resisting properties it has been progen ofwhich when set free adds its reducing posed to incorporate carbon in thebath of effect to that of the charcoal.

molten metal, a portion of the carbon com- There may also be added onthe surface of bining with the constituents of the alloy. the moltenbath, during the whole operation, The incorporation of carbon in thealloy a layer of material or a mixture of liquid and more especiallywith the aluminum or solid non-miscible substances capable of formingthe principal element of the latter constituting a protective layerwithout disgives to the metal which is produced very solving in theconstituents of the alloy. 66 good qualities of resistance to rupture,of Among these latter substances there may be elasticity and ofelongation, and at the same mentioned the carbides and certain stabletime a low density. reducing salts of various metals, which are Nowthese manufacturing processes are not apt to be displaced by aluminum intheir not wholly satisfactory owing to the fact combinations, alsovarious refractory clays that in order to produce a homogeneous Ofappropriate constitution, etc. metal and to avoid combustion of some ofits In order to insure the incorporation of constituents, they requirethat the bath be carbon in the alloy there may be added to perfectlyprotected in order to prevent surthe bath in the place of powdered orbrokenface or local oxidation. up charcoal, or together with the latterMy invention has for its object to obviate desired metal carbide such asiron, copper,

these drawbacks and to render the method of chromium, nickel, uraniumcarbides or any manufacturing technically and practically alloycontaining carbon in combination or applicable. It consists essentiallyin effectsolution such as carbon-chromium, carboning the treatment ofthe alloy in a reducing manganese, etc. 1

atmosphere in order to avoid alteration of In fact, it appearsadvantageous at the the aluminum caused by the oxidation or present time.to produce a high and coneven the dissolution of the gases. It maycontrollable percentage of chemically combined sist also in adding tothe bath of molten metal, carbon. Now the addition of a metal carbide,

3O constituents such as silicon and iron which the aluminum having ornot a tendency to Be improve the qualities and particularly the displacethe basic metal, appears to be the elasticity of the metal. It hasfurther for best means of producing a high percentage its object variousoperative methods which of combined carbon in the alloy. Even in will befully indicated in the following dethe case of the aluminum having notendscription. ency to substitute itself to the basic metal of 85 Thereducing atmosphere may be created to the carbide, the presence ofcarbon chemicalinsure the protection of the bath of molten ly combinedwith one of the constituents is of metal during the whole operation bymeans great value. of a layer of broken up charcoal or other A. partialvacuum or an atmosphere of reforms of carbon floating on the surfacetoducing or inert gases such as hydrogen, car- 90 gether with theaddition of powdered charbon monoxide or any other gas or gaseous coalor other forms of carbon in the bath mixture capable of fulfilling therequired and by combining both means of external conditions, such aslighting or coal gas,water and internal protection by carbon with thegas, the products of combustion of the fuel action upon or in the bathof solid liquid or used for heating the crucible, etc., may be gaseousbodies capable of ensuring the reducmaintained in the crucible above thesurface ing atmosphere required by the quality and of the bath of moltenmetal.

the regularity of the operation or of any Lastly, a current of reducinggas under substances contributing to the production of pressure may alsobe forced into the bath said ulluwphcrc. through the molten metal duringthe Whole 1 5! Elongation of operation said current of gas ensuring atthe same time the stirring of thebath.

This operation could be effected in a crucible having immersed therein atube in which the reducing gas would be forced and would rise again inthe shape of bubbles through the metal.

It could also take place in a kind of swinging converter similar to aBessemer converter in which the gas would be driven through the metal inthe same manner as air is driven through the molten metal in themanufacture of Bessemer steels.

In both the above cases there may be added to the reducing gas a certainquantity of superheated steam and the gaseous current may be chargedwith carbon by means of pulverized charcoal, graphite, coke or the like.The decon osition of the steam by the carbon owing the or" the bathwould then set free tain quantity of hydz--ogen in statu nascenoi, thehigh. reducing power oi the latter being added to that of the coal andof the gas.

It will be eyilent that these various means designed to create a ucingatmosphere in or upon the bath may be used separately or suitably combi1 As regards t .1 constitution of the alloy and in order 51-: i ve ithigher qualities of sins ticity there may be added preferably siliconfor example in the shape of cupro-silicon or of another combination ofsaid substance, the free silicon being absorbed by subsequently addingpure iron.

The aluminum alloys produced b means of my improved process are usua lyeonstituted by divers combinations of aluminum, copper, manganese,silicon, magnesium, iron and carbon. They may also comprise variousother constituents such as: tungsten, nickel, molybdenum, chromium, andcadmium, which may be added in varying quantitles according to thedesired results.

The following typical composition of ahighly resisting alloy obtained bythe above process is given as a particular example of an alloy accordingto the present invention: Aluminum opper agnesium anganese Carbon andother substances Resistance to fracture 4&5 pparent limit of elasticity31,2.

Density 1 -CllIGCE machining by The particular process of manufacture ofthis alloy will now be described also by way oi example:

The greater part of the aluminum (about or is melted and broken charcoalas well as a portion of the powdered charcoal is introduced into thebath which is then beated, when the latter has reached a temperaturesubstantially equal or higher (800 to 1,100") than the melting point ofaluminum, cupro-manganese, pure copper and cuprosilicon are added. Themixture is stirred and powdered charcoal moistened with water is added;the bath is stirred again and the heat ing is continued until thetemperature of 1100 to l200 has been reached and before the highertemperature has been reached there is added pure iron and powderedcharcoal moistened with Water, the mixture is again stirred and heatingis continued until the hi h temperature indicated has been. reached. Theremaining portion of the aluminum is then added, the bath skimmed andthe alloy produced is cast in ingots or pigs with the usual precautionsfor casting aluminum. The metal is finally rolled and annealed.

During the Whole melting process the reducing atmosphere has beenproduced by the combined action of carbon and of the hydrogen of thewater used for moistening the powdered charcoal and to this doubleaction may be advantageously added that of a reducing gas or of a solidor liquid reducing body in the above described conditions.

The alloy so manufactured lends itself to rolling, drawing, etc. themetal having acquired its characteristic properties which vary accordingto the rate of cooling.

The quantity of aluminum introduced at the beginning of the operationmay of course be reduced in order to obtain a rich metal which may besubsequently added to the pure aluminum or to a metal allo by melting.

My improved process may e applied to the direct manufacture of aluminumby adding in the crucible during electrolysis the carbon required and bycreating as above mentioned the reducing atmosphere for the bath, thusallowing the direct production of aluminum containing incorporatedcarbon. Other metal constituents may also be added in the crucihis inorder to produce immediately at the first melting the aluminum alloyscontaining carbon.

What I claim and desire to secure by Letters Patent of the United Statesis process for the manufacture of aluminum alloys containing carbonwhich consists in introducin' powdered charcoal and Water into themolten bath, protecting the surface of the said molten metal bath withbroken upcharcoal and operating at 9. tom-- perature above 900 C.

ANDRE GEYEB.

